1. Field of Invention
The present invention relates to a tightener for binding cargoes, in particular, to a ratchet wheel for a tightener, in the field of mechanics.
2. Related Art
Generally speaking, cargoes are required to be bound together while being transported by vehicles. It is lowly effective and laboursome to bind the cargoes by using nylon ropes or wire ropes. Meanwhile, the cargoes are difficult to be bound tightly. The Cargoes could be rapidly and conveniently bound and positioned by means of the tighteners. As a result, the tighteners are now widely applied.
The conventional tightener is composed of a body, a ratchet wheel, a baffle, a spring, a grip, a reel, a lateral plate, a mesh belt, a belt hook and so on. The ratchet wheel rotates in a single direction by turning the lateral plate, and then the mesh belt wrapped on the reel is continually frapped, so that two belt hooks are tightened on the cargoes or vehicle body.
In the conventional tightener, the reel consists of two half-moon keys of a semi-circular shape in section. Both ends of said two half-moon keys pass through the ratchet wheel respectively, and are fixed to each other by pins.
A large binding force is required when heavy cargoes are carried by vehicles, which is a challenge on the mechanical strength of the tightener. In fact, if the belts are frapped with an overlarge force when the cargoes are bound, the tightener would tend to be damaged.
In such a scenario, the ratchet wheel would be shifted from its original position, in which case the reel would be shifted accordingly. Consequently, the reel would be unevenly stressed, and the reel might be disengaged from the tightener in serious cases.
Similar drawbacks also occur in other conventional tighteners.